Building network automation solutions

6 week online course

Everyone talks about public or hybrid clouds, whitebox switching with home-grown networking operating system, or SDN nirvana, but whenever I talk with enterprise-focused architects, consultants or vendor SEs, I see a totally different story.

Here's a typical response I'm getting from engineers in this group: “I work with multinational financial customers, and in this group hybrid cloud is not even a topic. They do private cloud projects, with some of them looking into public cloud deployments of isolated projects on base AWS functionality.”

Imagine you get a routing outage in your network resulting in three minutes of traffic blackholing. After a few tense minutes it goes away and life is good, but you desperately want to know what went wrong. Can you figure it out? Well, you could if you were using PacketDesign tools, as Cengiz Alaettinoglu explained on Episode 51 of Software Gone Wild.

I somewhat expected that the leaf-and-spine fabrics designs webinar won’t be as short as I initially planned it to be, but when I started developing the scenarios and talking with guest speakers the whole thing exploded into a four-session saga (or maybe we’ll end up with the fifth session of a four-part trilogy).

Here’s a short update on what’s planned and where we are at the moment:

When you are talking about large-scale VLAN-based fabrics I assume that you are pointing towards highly populated VLANs, such as VLANs containing 1000+ Ethernet addresses. Could you provide a tipping point between reasonably-sized VLANs and large-scale VLANs?

It's not the number of hosts in the VLAN but the span of a bridging domain (VLAN or otherwise).

There were pearls of knowledge in there which expanded my understanding of ESX and gave me more than a few "aha!" moments […] The course is worth the money and time for sections "uplink redundancy & load balancing" and "VLAN based virtual networks" alone.

A while ago someone posted a link to an article that links to LinkedIn’s blog post describing their switch-building efforts to the LinkedIn SDN group (how’s that for a circular reference?), and a consultant from Brocade felt compelled to share his wisdom with the world. Unfortunately he got most of the facts wrong.

A few months ago VMware launched NSX version 6.2, and I asked my friend Anthony Burke to tell us more about the new features. Not surprisingly, we quickly started talking about troubleshooting, routing problems, and finished with route-health-injection done with a Python script. The end result: Episode 50 of Software Gone Wild. Enjoy!

With symmetric fabric… does it make sense for a node to know every bit of fabric info or is reachability information sufficient?

Let’s ignore for the moment that large non-redundant layer-3 fabrics where BGP-in-Data-Center movement started don’t need more than endpoint reachability information, and focus on a bigger issue: is knowledge of network topology (as provided by OSPF and not by BGP) beneficial?

While the large data centers increasingly use BGP as the routing protocol within their fabrics, the enterprise engineers tend to shy away from that idea because they think BGP is too complex/scary/hard-to-configure/obsolete/unknown/whatever.

Five years after the SDN hype exploded, it remains as meaningless as Cloud, and it seems that all we’re left with is a plethora of vendors engaged in SDN-washing their products.

Even when a group of highly intelligent engineers considering these topics on a daily basis gets together they don’t get very far apart from a great question: “what business problem is it supposed to solve?” (or maybe they got distracted by irrelevant hot-air opinions).

Is it still worth trying to find a useful definition of SDN? It seems it’s easier to list what SDN is not like I’ll be doing in the free Introduction to SDN webinar on February 10th. Let’s see:

Trying to fit my response into the huge Twitter reply field I wrote “Tracking Seq# on FW should be mostly irrelevant with modern TCP stacks” and when Gal Sagie asked for more elaboration, I decided it’s time to write a blog post.

The author

Ivan Pepelnjak (CCIE#1354 Emeritus), Independent Network Architect at ipSpace.net, has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced internetworking technologies since 1990.